1. Field of the Invention
The present invention relates to the field of the capture and disposal of evaporated, stored liquid fuels. In particular the invention relates to a means for burning gasoline vapors in an internal combustion engine, which vapors originate from storage of the gasoline in a tank.
2. Description of the Prior Art
Gasoline vapors are thermally generated in a vehicle fuel tank under normal conditions. Vapor ladened air is normally expelled from the fuel tank by normal thermal heating and expansion. The evaporated gasoline is collected in the tank and directed to the charcoal filled cannister. The evaporated gasoline is then adsorbed on the activated surface of the charcoal, and the purged air is then discharged to the atmosphere. The gasoline vapors, which are adsorbed on the charcoal within the cannister are then reutilized within an associated internal combustion engine.
However, when the engine is operating the gasoline vapors which have been adsorbed by the activated charcoal are entrained and carried by ambient air flowing into the cannister and are carried through a purge passage into the intake manifold of the associated internal combustion engine. Thus, the adsorbed gasoline vapors are ultimately utilized and supplied to the engine for combustion.
In the prior art gasoline vapor capture and combustion systems described above, the purge passage from the cannister communicates with the intake manifold of the carburetor at a point downstream from the air cleaner and upstream to the carburetor. Therefore, when the activated charcoal in the cannister is saturated and the engine is stopped, newly created gasoline vapors flowing into the cannister, are not adsorbed by the charcoal, but flow through the purge passage into the intake manifold of the carburetor. The intake manifold is thus filled with gasoline vapors which the cannister has failed to adsorb. As a result, in such prior art gasoline vapor capture and combustion systems, the gasoline vapors either completely fill the intake manifold when the engine is stopped or flow into the intake manifold through the purge passage of the charcoal cannister during start-up or during the idling operation of the engine. At these times, the presence of these vapors substantially infer with restarting the engine after the engine has reached or approached operating temperatures. In addition to substantially decreasing the ability to perform a warm restart of the engine, the presence of these nonadsorbed gasoline vapors during the idling operation of the engine causes the air-to-fuel ratio to fluctuate erratically, thereby causing the idling operation of the engine to become very unstable.
What is needed is a solution which provides a gasoline vapor capture and combustion system which prevents the emission of gasoline vapors into the atmosphere and yet burns the captured evaporated gasoline without inferring with or causing the engine operation to become unstable, particularly in warm restarts or during idling.